1. Field of the Invention
This invention relates in general to a method of manufacturing thin film electromagnetic flying head assemblies, and more particularly, to a method of integrating or combining a magnetic head/slider assembly with a silicon chip.
2. Description of Related Art
Disk drive systems are widely used to store data and software for computer systems. A disk drive system generally includes a disk storage media mounted on a spindle such that the disk can rotate thereby permitting an electromagnetic head mounted on a movable arm to read and write information thereon. Data read/write operations are performed by positioning the head to a selected radial position on the surface of the rotating disk. There the head reads or writes data in the form of magnetized regions on the platter coating.
The electromagnetic head for a disk drive system is usually mounted in a carrier called a "slider." The slider serves to support the head and any electrical connections between the head and the rest of the disk drive system. The slider maintains a uniform distance from the surface of the rotating disk to prevent the head from undesirably contacting the disk. This is accomplished by incorporating aerodynamic features into the slider that causes the slider to glide above the disk surface over the moving air.
Computer users constantly hunger for more and more data-storage capacity. Thus, disk drive makers are forever trying to increase the storage capacity of their products. In the process, they are also constantly trying to minimize the actual, physical size of those drives. The accomplishment of these goals requires both shrinking the spacing of the tracks so that more data can fit on a disk and squeezing bits more closely together on the tracks. Thus, disk drive manufacturers must develop heads that are narrower or that record narrower tracks.
Another very important parameter is the height at which the head flies above the surface of the platter. The magnetic field pattern around the gap in the head spreads and weakens very rapidly with distance away from the gap. Because the relevant distance is from the gap to the magnetizable platter coating, the design must include both the air gap (the actual height at which the head flies above the upper surface of the platter) and the thickness of any protective or lubricating overcoating that may have been applied to the platter. Thus, disk drive manufacturers must develop ways of minimizing the height at which the head flies above the disk surface while providing cost effective manufacturing techniques.
Still further, the air bearing surface area is proportional to slider flying height. In order to reduce the head/disk spacing, slider air bearing surface geometry and magnetic head features must therefore become smaller and more intricate. As the nominal head/disk spacing requirements shrink for each new product, air bearing rail and/or pad surface areas and magnetic head assemblies must also become smaller.
As the overall slider dimensions are reduced from nano to pico sizes and smaller to facilitate cost and productivity gains, the slider air bearing surface (ABS) and magnetic head features must also be proportionately scaled. This reduction in slider/head dimensions also increases the need to provide electrostatic protection to the magnetic head.
For example, a magnetic head may be disposed on a titanium carbide ceramic slider body of the dimensions of typically 2.5 mm by 1.7 mm and 0.425 mm thick. On the trailing edge of the magnetic head a magnetic sensor is formed on the edge. This sensor is attached to two gold pads. The magnetic sensor is approximately 2 microns long by 1 micron wide and formed using a 200 Angstrom thin film. This surface is coated with alumina insulator that is 2000 Angstroms thick followed by a permalloy shield made of nickel and iron. The resistance of the magneto-resistive (MR) head is approximately 50 ohms with the resistance of the leads to the gold pads being 10 ohms. Each of these critical elements of a magnetic head becomes more susceptible to destruction by electrostatic discharge as the dimensions are reduced. Nevertheless, any electrostatic discharge protection may be common to a variety of magnetic head designs. However, designing electrostatic discharge protection to each head design would significantly add cost to the head designs. Accordingly, disk drive manufacturers must search for ways to improve the fabrication of magnetic heads.
One example of the fabrication of a thin film head/slider combination is U.S. Pat. No. 5,095,613, issued Mar. 17, 1992, to Hussinger et al., entitled "THIN FILM HEAD SLIDER FABRICATION PROCESS", incorporated herein by reference, which discloses fabricating a head assembly from a bar on which electromagnetic devices are provided as a single row and with like orientation. The bar is integral along a second surface with an adjacent substrate portion. The bar is anchored to a fixture. Head assemblies are formed along the bar where immediately thereafter the individual head assemblies are separated. Then, the surface of the electromagnetic devices are exposed and processed. Finally, the exposed surface is lapped and ground until a desired throat height of the poles and a desired contour of the bar are obtained.
Another method of fabricating thin film head/slider combination is U.S. Pat. No. 4,333,229, issued Jun. 8, 1982, to Michael L. Ellenberger, entitled "METHOD OF MANUFACTURING THIN FILM MAGNETIC HEAD/SLIDER COMBINATION", incorporated herein by reference, which discloses depositing transducers onto a substrate member adjacent a finished and lapped surface in a manner such that no further lapping of the slider rail adjacent the transducer is required. The method includes forming recesses on the substrate member to define slider rails and then forming air bearing surfaces on each rail.
While each of the above patents disclose methods for consolidating an air bearing slider with a magnetic head, the integration of a magnetic head assembly with electrostatic protection and additional circuitry is not provided.
Thus, it can be seen that there is a need for providing a method of combining a magnetic head assembly with a silicon chip containing additional circuitry such as electrostatic discharge protection circuitry, signal processing circuitry or memory circuits.
It can also be seen that there is a need for integrating a silicon chip providing electrostatic protection and other required circuitry with a magnetic head assembly.